The invention relates to a method for reactive vapour deposition of compounds of metals and semi-conductors on to at least one substrate by a glow discharge inside a space between a vaporising cathode having a target of metal or semi-conductor and the substrate while feeding an inert gas and a reaction gas for the formation of the desired compound, in which the reaction gas is added to the mass flow on its way from the target to the substrate, by means of a distributing device, into a plurality of partial streams, and in which the glow discharge is concentrated by a closed magnetic field in a region in the neighbourhood of the target face.
Reactive vapour deposition is used whenever compounds of metal and semi-conductors, for example, oxides, are to be produced on substrates, which compounds cannot at all or only with difficulty be sputtered in compound form. So, for example, a target composed of silicon dioxide can only be vaporised at high frequencies and even then only at a low rate, while the atomisation of silicon is possible even at high rates by direct current.
Similar facts apply in vapour depositing layers of aluminium oxide. While it is extraordinarily difficult to vaporise target plates of A1.sub.2 O.sub.3 at anything like a useful rate, a metallic target of aluminium can be vaporised without difficulty at a high rate. This vaporisation process however gradually comes to a halt in reactive atmospheres, that is to say gas atmospheres containing oxygen, because the target face forms aluminium oxide, which does not conduct electricity, so that it prevents the escape of electrons. These considerations also apply with other metals or semi-conductors, whenever they are vaporised in reactive atmospheres using direct current. Such processes can also be characterised as unstable.
The formation of an oxide layer on the target face gives rise to electrical discharges, besides, which discharge the target face from time to time and thus disturb the vapour deposition process.
From DE-PS No. 29 02 142 it is known, in a comparable process, in which however the magnetic field has another configuration in the region of the target face, to add the reaction gas to the mass flow on its way from the target to the substrate in a number of partial streams. This is done by means of an annular distributor, which is provided with a plurality of exit bores for the reactive gas. With such a method, however, the formation of insulating reaction products on the target face is not precluded, even if the distributor arrangement is a part of the work piece mount or the substrate holder in the immediate vicinity of which the chemical reaction is to be carried out. Quite obviously the reaction gas comes into contact with the target face and produces there the layer, for example an oxide layer, of reaction product that gradually brings to a standstill the vaporisation process.
The invention is based on the problem of providing a method of the above described kind in which the vaporisation process, despite the constant supply of reactive gas can remain stable over long periods and in which the vaporisation rate from targets of metal and semi-conductors is achieved.